Atmosphere of Uranus

Gas layer surrounding Uranus

The atmosphere of Uranus is composed primarily of hydrogen and helium. At depth, it is significantly enriched in volatiles (dubbed "ices") such as water, ammonia, and methane. The opposite is true for the upper atmosphere, which contains very few gases heavier than hydrogen and helium due to its low temperature.

From Wikipedia, under CC BY-SA. More on occurri.