Neptune is the eighth and farthest planet from the Sun in Sol. In Sol, it is the fourth-largest planet by diameter, the third-most-massive planet, and the densest giant planet. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times the mass of Earth and slightly larger than Neptune. Neptune orbits the Sun once every 164.8 years at an average distance of 30.1 astronomical units (4.50×109 km). It is named after the Roman god of the sea.

As of 2180, the Triton Research Station has been built on the planet's largest moon, dedicated to researching Neptune itself as well as its thirteen other moons. A small colony was also established on Triton after the discovery of the moon's subsurface ocean, and there are a number of mining facilities among Neptune's other moons.


While it was established over a hundred years ago, the colony established on Triton is still very small compared to other Human colonies such as Exodus and Genesis. Primarily for the purposes of mining now, it was once considered a tourist destination much like Mars before the United Nations ventured beyond the Sol sector.