This is a diagram of diffusion in the Uranian atmosphere.
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Diffusion in Uranus Atmosphere

Uranus' atmosphere is made of methane, a medium sized molecule. At the uppermost reaches of the atmosphere, methane gas breaks apart due to energy from the sun and from the magnetosphere. The remins of this methane combine with other gases to form complicated large molecules such as ethane gas, and acetylene. These gases are heavier, and so drop down in the atmosphere.

In regions of the atmosphere where the temperature is cooler, these gases form droplets of haze and smog. At even lower altitudes clouds of methane, ethane, and acetylene form.

At the bottom of the atmosphere, where the temperature warms up and changes to the Uranian interior, the molecules evaporate and break apart again into the methane and the other parts which made it in the first place. These smaller molecules return to the top of the atmosphere by diffusion.

This constant breakdown and assembly of methane and ethane is part of the evolution of Uranus and affects its weather.


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