Neptune
is another bluish gas giant, close to the size of Uranus. Like Uranus,
it also has faint rings, but again not as impressive as those of Saturn.
Neptune has a giant spot, like the red one of Jupiter, referred to as the
"Giant Dark Spot" that seems to occasionally disappear and later reappear
in another location. The spot itself is about the size of Earth.
Like it's neighbour Pluto, Neptune was late to be discovered, since it
cannot be seen with the unaided eye. It was discovered in the 1800's
by astronomers.