Neptune

The eigth planet, Neptune, was discoveted  in  1846 by  astronomer Johann Gottfried Galle. We have already told you  the story of  its discovery  in last. It  is so far awaythat, seen from Neptune, the Sun must appear just  as a bright point. Neptune's atmosphere has methane hut no detectable ammonia. Its cloud  temperature is about -237°C.  Neptune is orbited by Triton, one of  the biggest satellites in the Solar System.It orbits Neptune in a clockwise drrection, i.e. opposite to the planet's own rotation.  It has an atmosphere of nitrogen and methane. It may even have an ocean of  liquid nitrogen.  'lhton is acmmpanied by  a smaller satellite, Nereid. In 1989, Voyager 2- passed within 35,000  km of Neptune and  within 40,000 km of Triton resulting in a significant  increase  in our knowIedge about Neptune and  its satellites.