So finally in our little series about the planets we are talking about Neptune. The eighth planet in our solar system, and the furthest from the Sun. It is a gassy planet but is also classified as an Ice Giant (I'm voting for renaming it Loki), but this means that there is more water, ammonia and methane than in planets like Saturn! Neptune is named after the Roman god of the Sea, or Poseidon if you are from Greece! Although Galileo did see Neptune in 1612, it was not officially discovered as a planet in 1846.
Neptune is pretty massive and weights about 17 Earths. It is made of mostly gases, but has rocky core which is bigger than Earth! It is so far away from the Sun that most of the heat is generated by the planet itself, but the atmosphere has a temperature of almost 450 degrees Celsius (which is pretty darn hot!) so Neptune is generating a lot of heat!
This is an image taken by Voyager 2 in the 80s.
Neptune has a ring system (like Saturn), but it is really hard to see in visible light. They are mostly made of ice, but instead of Saturn's pure white rings, Neptune's is a reddish colour. They are also pretty unstable compared to Saturn's. Neptune has 14 moons, the largest of which is called Triton (who was the son of Poseidon) and is one of the largest moons in the solar system! We haven't really explored Neptune very much, but hopefully soon they'll launch a new satellite that can tell us more about this distant, mysterious planet!
What do you think about this lonely planet? Is there anything Astronomy you'd like me to cover? (I promise black holes are coming soon!)