Uranus’ atmosphere is mainly composed of helium and hydrogen. A large part of its atmosphere is also composed of water, ammonia and methane. The surface below its upper atmosphere is filled with a “sea” of ammonia, water and hydrogen. The transition from liquid to gas in the atmosphere is not clear. The part of the atmosphere that is filled with gas contains hydrogen and helium. Uranus and Neptune are known for being the ice giants because of their composition. The atmosphere of Uranus is divided into three parts: the troposphere, the stratosphere, and the thermosphere (also known as the corona).
The troposphere is the lowest and most dense part of the Uranus’s atmosphere. As the altitude increases the temperature decreases. The troposphere contains many different and complex cloud structures. The clouds that appear in the troposphere depend on the pressure of each location. Clouds made up of water are said to be located at pressures ranging from 50-100 bar. Clouds made up of ammonium hydrosulfide are located in pressures that range from 20-40 bars.
Hydrogen sulfide and ammonia clouds are located at pressures between 3-10 bars. Located at pressures ranging from 1-2 is a very thin layer of methane clouds. Changes in seasons, strong winds, convections and bright clouds are typical occurrences in the troposphere.
The stratosphere is the middle part of the atmosphere. Haze layers made up of acetylene and ethane form in the low part of the stratosphere and tropopause. This may be part of the reason why Uranus has such a bland color.
The thermosphere/corona makes up the outermost layer of the atmosphere. Helium is absent in this part of the atmosphere. The thermosphere has an abundant amount of molecular hydrogen as well as hydrogen atoms. Because these molecules mass together coupled with the high temperature of this region explains why this part of the atmosphere is so large. The thermosphere is around 50,000 km away from the planet itself. This quality is unique to Uranus. Because of this small particles which orbit Uranus are dragged to the atmosphere which lessens the dust on the rings of Uranus.
Rings of Uranus