Unusual Feature
Since Neptune's Orbit is so far from the sun, it receives a very small amount of heat and indeed the uppermost region of the atmosphere is -218 °C. Atmospheric temperatures gradually rise as you go deeper inside Neptune due to an internal source of heat. It is thought that this may be leftover heat generated by in falling matter during the planet's birth, right now slowly radiating away into space. Neptune's atmosphere has the highest wind speeds in the solar system, up to 2000 km/h, thought to be powered by this flow of internal heat. There is no solid surface due to the fact that Neptune is a gas giant. The internal structure resembles that of Uranus.