NEPTUNE

Neptune was first identified as a planet in 1846 by the German astronomer Johann Gottfried Galle. Neptune is the fourth of the gas giants. It is sllightly smaller than Uranus. The violent winds in Neptune's deep atmosphere - the strongest in the whole Solar System - rage at more than 1,100 kilometres per hour. The tops of the gas clouds are featureless, and there remains much to be learned about this distant world.

Long, wispy clouds race around Neptune. They are blown by the fastest winds found on any planet in the Solar System. Near the Great Dark Spot, the winds blow at up to 2,000 kmph. One cloud zooms around Neptune once every 16 hours. Scientists have nicknamed this cloud the Scooter, because it scoots over the planet so quickly. Neptune has twelve moons. The biggest of them are Triton and Nereid. Trion is even bigger than the planet Pluto. Unlike most moons, it orbits in the opposite direction to Neptune's spin.