As the eighth planet from {{UsefulNotes/the Sun}}, its blue hue caused it to be dubbed "Neptune" after the Roman God of Sea. (Though Modern Greece calls it "Poseidon"). Neptune is a gas giant. Similar to {{UsefulNotes/Jupiter}}'s Great Red Spot, Neptune has its own series of atmospheric storms collectively titled as " The Great Dark Spot". That is, until it disappeared sometime before 1994.

Neptune has the honor of being the first planet to be discovered with mathematics as opposed to actually astronomic observation. Fitting since it can never be observed from {{UsefulNotes/Earth}} without a telescope. First spotted way back in the 1610s, Galileo mistook the planet for a fixed star due to Neptune had begun its apparent retrograde motion that same day. When predictions for {{UsefulNotes/Uranus}}'s orbits were proven to be off, it became hypothesized that another planet was exerting some gravitational force. After years of calculations, Urban Le Verrier proved Neptune's existence. Triton was found just seventeen days later.

It would take until the 20th century to discover its ring system as well as any new moons, the bulk of which were discovered by Voyager 2. Even so, the most recent discovery coming in July of 2013 showed that the probe had missed some moons, bringing Neptune's moon count up to fourteen.