The natural blue light is coming from the oxygen in the atmosphere but it's so overwhelming in that spot that it turns the light pure white. The red/orangish is coming from particulates and the green/red from aurora. My favorite part I think is the very bottom where you can see the blue light taper off and not overwhelm the camera sensor and you can see the aurora with it. I love this photo so much.
Probably my favorite photo ever now.
And all the others are negligible by many orders of magnitude compared to the moon. So it's really just the moon as far as this photo is concerned (except for the small sliver that's still illuminated by sunlight, including refracted sunlight).
This is true for every photo ever taken
That's highly incorrect. I have many lightsources that aren't contributing to any photons in that picture. For example my refrigerator light.
Yes, exactly.