This photo illustrates three phenomena that surprised me when I arrived on board the @iss. I didn’t realize before seeing it with my own eyes that the Earth’s atmosphere would be so visible in the night sky, seemingly even more obvious at nighttime than daytime, nor that it would be so colorful! These orange and green colors on the horizon are airglow, a faint emission of light caused by chemical reactions and interactions between UV radiation and gases in our atmosphere (unlike aurora, which is caused by solar wind particles interacting with Earth’s magnetic field, airglow is present everywhere, all of the time). I was also surprised to see how blue and well lit the Earth can be at night, when a bright Moon illuminates it (Moonglow!). This photo was taken on May 30, the day prior to the full Moon. I hope that this provides a bit more @nasaartemis Moon Joy for all of us!