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Neptune is the eighth planet from the Sun, making it the most distant in the solar system. This gas giant may have formed much closer to the Sun in the early solar system history before migrating out to its current position.

Facts about Neptune

Neptune is the most distant planet from the Sun.

Neptune is the smallest gas giant.

A year on Neptune lasts 165 Earth years.

Neptune is named after the Roman god of the sea.

Neptune has 6 faint rings.

Neptune was not known to the ancients.
It is not visible to the naked eye and was first observed in 1846. Its position was determined using mathematical predictions. It was named after the Roman god of the sea.

Neptune spins on its axis very rapidly.
Its equatorial clouds take 16 hours to make one rotation. This is because Neptune is not solid body.

Neptune is the smallest of the ice giants.
Despite being smaller than Uranus, Neptune has a greater mass. Below its heavy atmosphere, Uranus is made of layers of hydrogen, helium, and methane gases. They enclose a layer of water, ammonia and methane ice. The inner core of the planet is made of rock.

The atmosphere of Neptune is made of hydrogen and helium, with some methane.
The methane absorbs red light, which makes the planet appear a lovely blue. High, thin clouds drift in the upper atmosphere.

Neptune has a very active climate.
Large storms whirl through its upper atmosphere, and high-speed winds track around the planet at up 600 meters per second. One of the largest storms ever seen was recorded in 1989. It was called the Great Dark Spot. It lasted about five years.

Neptune has a very thin collection of rings.
They are likely made up of ice particles mixed with dust grains and possibly coated with a carbon-based substance.

Neptune has 14 moons.
The most interesting moon is Triton, a frozen world that is spewing nitrogen ice and dust particles out from below its surface. It was likely captured by the gravitational pull of Neptune. It is probably the coldest world in the solar system.

Only one spacecraft has flown by Neptune.
In 1989, the Voyager 2 spacecraft swept past the planet. It returned the first close-up images of the Neptune system. The NASA/ESA Hubble Space Telescope has also studied this planet, as have a number of ground-based telescopes.

Neptune Diagrams

Neptune size compared to Earth

Neptune distance from the Sun and orbital eccentricity

Neptune's Great Dark Spot

The Great Dark Spot in the southern atmosphere of Neptune was first discovered in 1989 by the Voyager 2 spacecraft. It was an incredibly large rotating storm system with winds of up to 1,500 miles per hour, the strongest winds recorded on any planet. How such powerful winds were discovered on a planet so far from the sun is still considered a mystery to this day.

Data from the Voyager 2 spacecraft also showed that the Great Dark Spot varied significantly in size during their brief pass of the planet. When Neptune was viewed by the Hubble Space telescope in 1994 the Great Dark Spot had vanished, although a different dark spot had appeared in Neptune's northern hemisphere.

Neptune's Atmosphere

Neptune has an incredibly thick atmosphere comprised of 74% hydrogen, 25% helium and approximately 1% methane. Its atmosphere also contains icy clouds and the fastest winds recorded in the solar system. Particles of icy methane and minor gases in the extremities of the atmosphere give Neptune its deep blue colour. The striking blue and white features of Neptune also help to distinguish it from Uranus.

Neptune's atmosphere is subdivided into the lower troposphere and the stratosphere with the tropopause being the boundary between the two. In the lower troposphere temperatures decrease with altitude however they increase with altitude in the stratosphere. Hydrocarbons form hazes of smog that appear in the entire upper atmosphere of Neptune and hydrocarbon snowflakes that form in Neptune's atmosphere melt before they reach its surface due to the high pressure.

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Neptune Facts - Interesting Facts about Planet Neptune

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Neptune is the eighth planet from the Sun, making it the most distant in the solar system. This gas giant may have formed much closer to the Sun in the early solar system history before migrating out to its current position. Neptune is the most distant planet from the Sun.

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Voyager 2 is the ONLY human-made object to have flown by Neptune.

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In the summer of 1989, NASA's Voyager 2 became the first spacecraft to observe the planet Neptune, its final planetary target. Passing about 4,950 kilometers (3,000 miles) above Neptune's north pole, Voyager 2 made its closest approach to any planet 12 years after leaving Earth in 1977. Five hours later, Voyager 2 passed about 40,000 kilometers (25,000 miles) from Neptune's largest moon, Triton, the last solid body the spacecraft will have an opportunity to study.

Neptune is one of the class of planets -- all of them beyond the asteroid belt -- known as gas giants; the others in this class are Jupiter, Saturn and Uranus. These planets are about 4 to 12 times greater in diameter than Earth. They have no solid surfaces but possess massive atmospheres that contain substantial amounts of hydrogen and helium with traces of other gases.

Voyager 1, launched September 5, 1977, visited Jupiter in 1979 and Saturn in 1980. It is now leaving the solar system, rising above the ecliptic plane at an angle of about 35 degrees, at a rate of about 520 million kilometers a year.

Voyager 2, launched August 20, 1977, visited Jupiter in 1979, Saturn in 1981 and Uranus in 1986 before making its closest approach to Neptune on August 25, 1989. Voyager 2 traveled 12 years at an average velocity of 19 kilometers a second (about 42,000 miles an hour) to reach Neptune, which is 30 times farther from the Sun than Earth is. Voyager observed Neptune almost continuously from June to October 1989. Now Voyager 2 is also headed out of the solar system, diving below the ecliptic plane at an angle of about 48 degrees and a rate of about 470 million kilometers a year.

Both spacecraft will continue to study ultraviolet sources among the stars, and their fields and particles detectors will continue to search for the boundary between the Sun's influence and interstellar space. If all goes well, we will be able to communicate with the two spacecraft for another 20 years, until their radioactive power sources can no longer supply enough electrical energy to power critical subsystems.

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In the summer of 1989, NASA's Voyager 2 became the first spacecraft to observe the planet Neptune, its final planetary target. Passing about 4,950 kilometers (3,000 miles) above Neptune's north pole, Voyager 2 made its closest approach to any planet 12 years after leaving Earth in 1977.

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Yes!! Neptune makes lots of sound!!

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Neptune's made up of hot dense fluid of "icy"- water methane and ammonia.

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Neptune's clouds are cirrus clouds made up of frozen methane. Frozen Methane is made up of methane gas molecules locked inside frozen water molecules.

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Neptune's atmosphere is made up of hydrogen, helium, and methane. Like Earth's atmosphere, Neptune's has clouds and storm systems that revolve around the planet, but with wind speeds of 300 m/sec (700 mi/hr), and clouds of frozen methane.

The "Great Dark Spot" discovered by Voyager 2 is a huge storm system that resembles Jupiter's Red Spot, and is surrounded by white cirrus clouds of frozen methane. More recent views of Neptune from the Hubble Space Telescope show no signs of the Spot, indicating that it has vanished over the years.

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Neptune's atmosphere is made up of hydrogen, helium, and methane. Like Earth's atmosphere, Neptune's has clouds and storm systems that revolve around the planet, but with wind speeds of 300 m/sec (700 mi/hr), and clouds of frozen methane.

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Click the link to find out!!

Neptune has nine rings five main ones, and four prominent rings.

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Yes, Neptune has several faint rings around it. There are three main rings which are very thin and dark. The rings are made up of small rocks and dust. Neptune's rings are not the same thickness all around. There are areas of the rings which are much thicker than other areas of the rings. These thicker parts are called ring arcs. Some of these ring arcs are also twisted. Because Neputune's rings are so dark and faint, they were not discovered until the 1980s.

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Javascript must be enabled to use Cool Cosmos. Learn how. Yes, Neptune has several faint rings around it. There are three main rings which are very thin and dark. The rings are made up of small rocks and dust. Neptune's rings are not the same thickness all around.

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Here are most of Neptune moons.
Triton is the biggest moon for Neptune!!

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Click on the link to learn a lot more about the Big Blue Giant