Neptune is an icy ball of gas located 30 Astronomical Units from the sun. Neptune is the outermost planet in the Solar System as Pluto (and other similar bodies further out than Neptune) are now called Dwarf Planets. Neptune is nearly as large as 60 Earths. It orbits the sun in 165 years and turns once on its axis in 16 hours. Neptune has 8 known moons and Voyager 2 discovered 6 of them. Neptune also has rings like Jupiter and Saturn and Uranus [1].


It appears that the outer part of Neptune consists of helium, hydrogen, methane and water while the interior has molten rock and liquid ammonia. Further Neptune is a very windy place. Winds of 2,000 kilometers (1,200 miles) an hour have been measured.

It once had a big dark spot on it, like Jupiter's big red spot, but that went away.


Neptune was discovered in the middle of the 19th Century after a mathematician named Le Verrier analysed irregularities in the orbits of Uranus and predicted that there was another planet influencing Uranus. We aren’t sure if Le Verrier was clever or lucky. [2]


-September 23, 1846
-by Johann Gottfried Galle

Distance discovery and visits

  • Eighth planet from the sun, fourth largest in diameter
  • 1613-Galileo observed Neptune when it was near Jupiter
  • has only been visited by one spacecraft, Voyager 2 on Aug 25 1989
  • the smallest of the four "gas giants"


  • average distance from sun: 2.8 billion miles
  • diameter: 49,532 km (equatorial)
  • mass: 1.0247e26 kg
  • atmosphere: mostly hydrogen and helium with a small amount of methane
  • average cloud temperature: from -240 degrees to 330 degrees F
  • average temperature on Neptune: -373 degrees F
  • orbits the sun every 165 years
-a day on Neptune is about 16 hours 6.7 minutes
  • tilt of axis: 28.32 degrees
  • for brief periods of time Neptune crosses Pluto's highly elliptical orbit, making Pluto the 8th planet from the Sun and Neptune the furthest

Neptune's Color

-absorption of red light by methane in the atmosphere
-unidentified chromophore


-rapid and causes large storms or vortices
-fastest in the solar system
-reaching 2000 km/hour

Internal heat source

-radiates more than twice as much energy it recieves from the sun

==The Great Dark Spot

-a great storm which moves about 700 mph
-Neptunes most prominent feature
-Southern hemisphere
-about the same diameter as the Earth
-generates cirrus clouds made of crystals of frozen methane
-seems to have disappeared and returned in another area

The Skooter

-small irregular white cloud
-passes around Neptune every 16 hours

Neptune's rings

-four rings
-one ring has an odd twisted structure
-they are very dark but their composition is unknown
-each ring has a name
-outermost: Adam-contains three prominent arcs named Liberty, Equality and Fraternity
-an unnamed ring co-orbital with Galatea
-Leverrier-outer extensions are called Lassell and Arago
-lastly- Galle: faint but broad

Neptune's Moon -largest Moon is Trition

Roman Mythology: Neptune (Greek: Poseidon) was the god of the sea

References and External links


Copied from Liberapedia