Neptune is the eighth planet in order of increasing distance from the sun. Its average distance is 2.796 billion miles from the sun. 84 percent of the light falling on it from the sun is reflected. A day on Neptune lasts about 16 hours, and a year on Neptune is about 165 earth years. The temperature surface of Neptune is about -360 degrees Fahrenheit. The atmosphere consists mostly of hydrogen and helium, but the presence of methane gives the planet its blue color. Neptune has eight known satellites and is circled by five thin rings.