Airglow over Alberta, Canada
Airglow is the light of excited atoms high in Earth’s atmosphere. Here’s an explanation from NASA Earth Observatory:
The phenomenon typically occurs when molecules (mostly nitrogen and oxygen) are energized by ultraviolet (UV) radiation from sunlight. To release that energy, atoms in the lower atmosphere bump into each other and lose energy in the collision. But the upper atmosphere is thinner, so atoms are less likely to collide. Instead they release their energy by emitting photons. The result is colorful airglow.
Yuri Beletsky Nightscapes captured this image in Banff National Park in Alberta, Canada. in October 2018. Yuri said:
Here you can see a view of a river, with the prominent Big Dipper just above the mountains. Airglow waves were all over the sky!
Thank you, Yuri!
Want to know more about airglow? Here’s a video from NASA.
Bottom line: Photo of airglow and Big Dipper over Banff National Park, Alberta, Canada, and video explaining airglow.