Not every experiment turns out as expected. Photographer Julien Looten expected to capture the Milky Way arching across the sky above this French chateau. But the photo’s most striking feature is instead the airglow suffusing the sky. The psychedelic colors result from air high in Earth’s atmosphere getting excited by sunlight and producing a faint glow of its own. Such airglow is common, though not always easily seen. If you watch videos from the ISS, you may notice the orange arc of airglow over the atmosphere. (Image credit: J. Looten; via APOD)
Celebrating the physics of all that flows