I found this video today. The video was made by Dr. Alex Rivest and he explains more about it on his blog.
Apparently, the Earth’s atmosphere gives off its own glow through a process called chemoluminescence. During the day UV light from the sun excites oxygen and nitrogen atoms in the thermosphere. At night, the atoms lose this energy and give it off as photons.
There is some cool science, but mostly the zen-nature of the video makes my heart happy.