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Neptune is the 8th planet from the Sun. The planet is classed as a gas planet. Neptune derives its name from the Roman god for God of the Sea. Neptune was discovered by Johann Elert Bode in 1781. The mass of the object is 102.43. The equatorial radius of the planet is 24764 whereas the volumetic mean radius is 24624. The Mean Density of the planet is 1638. The surface acceleration of the planet is 11. The time the planet takes to revolve round the Sun is 60189 days or roughly 164.9 Earth Years. The length of a day on the planet is 16.11 hours, i.e. the time it takes to revolve once on its axis. The average temperature of the planet is -72K/-201C. The surface pressure of the planet is >1000bars.

Neptune is about 4495100000.0km from the Sun. The Orbit Eccentricity is 0.0113, that is how much the orbit deviates from a circle, between 0 and 1. The Orbit Inclination is 1.769, that is how much the orbit deviates from a circle, between 0 and 1. The volume of Neptune at the equator is 6254. The escape velocity, the speed which is need to break free is 23.5. The surface gravity of Neptune is 11.15 compared to Earth which for purpose of this site is 1. The following gasses can be found in the Neptune's atmosphere : Molecular hydrogen (H2) - 80.0% (3.2%); Helium (He) - 19.0% (3.2%); Methane (CH4) 1.5% (0.5%)\n. More information and the source for the moon can be found at N.A.S.A.

Neptune was discovered by calculation and observation. Once Uranus had been discovered, the search was on for other planets that could lie outside the orbit of Uranus. Neptune, named after the Roman God of Water was finally discovered 23rd September, 1846. Johann Galle is most closely associated with discovering the planet, but without the assistance of John Couch Adams and Urbain Le Verrier, it would not have been possible. Neptune is the smallest and most remote of the gas giants. Since Pluto was downgraded to Dwarf planet, Neptune is now the furthest planet from the Sun. Neptune has a deep blue appearance and therefore it was only apt to name the planet after the Roman God.

When Voyager 2 past the planet in 1989, Neptune was discovered to have a faint ring system like the other gas giants.


In the film Event Horizon, the planet is the background setting for the return of a space ship that had disappeared years in the past. All the film happens onboard the craft, there is no voyaging into Neptune or one of its moon. The core of the planet maybe rock but then again it might not be, we don`t know for certain. You wouldn`t be able to enter the planets atmosphere as it would be too hostile.

Neptune Facts

Position from Sun8 A.U.
MeaningGod of the Sea
DiscovererJohann Elert Bode
Equatorial Radius24764
Volumetric Mean Radius24624
Mean Density1638
Surface Acceleration11
Orbital Period60189 Days
Length of Day16.11
Average Temperature-72K/-201C
Surface Pressure>1000bars
Distance from the Sun4495100000.0km from the Sun.
Orbit Eccentricity0.0113
Orbit Escape Velocity23.5
Surface Gravity11.15
AtmosphereMolecular hydrogen (H2) - 80.0% (3.2%); Helium (He) - 19.0% (3.2%); Methane (CH4) 1.5% (0.5%)\n

List of Moons in orbit around Neptune

MoonDiscoveredOrbit Circumference
Galatea1989 389,262.18 km
Halimede14 August 2002 102,518,463.80 km
Laomedeia13 August 2002 142,059,611.72 km
Larissa1982 462,115.49 km
Naiad1989 303,019.17 km
Nereid1949 29,067,053.44 km
Neso2002 282,584,902.19 km
Proteus1989 739,191.57 km
Psamathe29 August 2003 290,917,287.50 km
S/2004 N11 July 2013 661,512.60 km
Sao14 August 2002 139,009,795.11 km
Thalassa1989 314,624.22 km
Triton1846 2,229,016.54 km

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