This is an image of Neptune and its famous Great Dark Spot. Click on image for full size (32K JPG) Courtesy of NASA

Neptune was discovered in 1846. But it wasn't discovered using a telescope. Scientists used math instead! They watched Uranus and saw that its orbit was doing weird things. They knew another planet had to be changing it. They were right!

Neptune's largest moon, Triton, was discovered at the same time as Neptune. Another moon called Nereid was found in 1949. Neptune's other six moons were found by Voyager II in 1989. Voyager II took many pictures of Neptune and its moons. Almost everything we know about this planet came from the Voyager II mission.

Neptune is usually the eighth planet out from the Sun. But sometimes Pluto actually crosses in front of it! Neptune was named after the ancient god of the seas.