Eighth planet from the Sun. Deep azure blue from atmospheric methane. Home to the fastest winds in the solar system — over 2,000 km/h.
Neptune is the only planet found by mathematical prediction before being seen. Its deep blue color comes from methane absorbing red light. Winds whip around at supersonic speeds.
Voyager 2 saw a Great Dark Spot the size of Earth in 1989. By the time Hubble looked in 1994, it was gone — replaced by new dark spots. These are anticyclonic storms that form and dissipate every few years.
Triton orbits Neptune backwards (retrograde), meaning it was captured from the Kuiper Belt. It's one of the coldest objects in the solar system (-235°C) and has active geysers that erupt nitrogen gas.
Neptune has five main rings, but they're not uniform — they're clumpy. The outer ring contains bright arcs of concentrated material, held in place by the gravity of a tiny shepherd moon.
Galatea is a tiny shepherd moon. Its gravity creates resonances that trap ring particles into stable clumps — the arcs we see today.
Voyager 2's 1989 Neptune flyby was humanity's last visit to an outer planet. It discovered 6 new moons, the rings, and the Great Dark Spot. No spacecraft has returned since.