Neptune has an atmosphere full of
hydrogen, helium and methane. It has at least four rings that are very faint and
has eight moons. Clouds of methane ice surround the dark spot, which is a storm,
towards the middle of the planet. Neptune has a stormy atmosphere and appears to
be blue because there is more methane ice in the top levels. Neptune’s average
temperature is –355F in the day. At night, the temperature drops rapidly.
Neptune was discovered in 1846. The
planet remained almost unknown until 1989, when space probe Voyager 2 flew
passed it. Neptune is four times wider than the Earth with a diameter of 30,800
Neptune’s largest moon is Triton.
The cold moon has an average temperature of –391F in the daytime and at
nighttime it’s even lower, which makes it the coldest known place in the solar
system. Triton has a diameter of 1,680 and is slightly larger than Pluto. It is
covered in methane frost and nitrogen. Brrr. Imagine trying to walk on that!