Welcome to the eighth (or ninth) planet from the Sun (sometimes the farthest, depending on Pluto’s attitude and status as a planet)! The fourth largest planet in the Solar System by diameter, Neptune was named for the Roman (or Greek, by another name) God of the Sea after people realized that Planet Exterior to Uranus just didn’t sound cool. The name is fitting in the sense that the planet is partially composed of water. Aside from H2O, Neptune consists of ammonia, methane, hydrogen, and helium. Good luck with landing a spacecraft here, by the way! The planet is composed of ice and rock surrounded by gas clouds that are blue because its atmosphere absorbs red light. The composition isn’t layered, though; the various ingredients are more evenly spread out.
At a distance of 30.06 Astronomical Units from the Sun, or 30.06 times farther from the Sun than Earth is, you can bet Neptune will take its time and complete an orbit in several Earth years — 164.79 to be exact! The days are shorter, though; only sixteen hours in a day will ensure that time will fly when you’re having fun on vacation. Surely you’ll feel right at home on a planet with a gravitational acceleration constant of 11.15 m/s^2, just greater than Earth’s, to keep you attracted. Neptune has a mass of 1.02×10^26 kilograms and a volume of 6.254×1013 km^3, which makes for a density of 1.64g/cm^3, almost double that of water.
Neptune has a familiar axial tilt 28.32 degrees, which an Earthling might find comforting because it makes Neptune that much closer to home. Pack a jacket, though, and watch out for the weather! The surface temperature on Neptune is -218 degrees Celsius, almost as cold as a standardized testing room. Neptune has the fastest winds in our Solar System; speeds reach approximately 2000 km/hr, and they travel in bands of latitude and in small storms or vortices. Also, Neptune has an angled magnetic field 27 times stronger than Earth’s that changes due to interaction with solar wind.
Want to go on a vacation within a vacation? Not a problem; you’d have lots of nearby potential travel destinations on any of Neptune’s 14 natural satellites. Take a trip to Naiad, Thalassa, Despina, Galatea, Larissa, Proteus, Triton, Nereid, Halimede, Sao, Laomedeia, Psamanthe, or Neso. Or go ahead and colonize S/2004 N 1 and give it a proper name. Neptune also has six rings named for people who’ve researched it. Speaking of, there was some controversy about who discovered Neptune, but it’s pretty much agreed upon that Galle, Le Verrier, and Adams all made important contributions. Also, Neptune was the first planet in our Solar System to be located using math instead of observation — congratulations for being located, Neptune! *
(P.S. check out this rad video of Neptune making sounds)