Posted by Specola

NASA Astronomy Picture of the Day:

Yes, but can your aurora do this? First, yes, auroras can look like rainbows even though they are completely different phenomena. Auroras are caused by Sun-created particles being channeled into Earth's atmosphere by Earth's magnetic field, and create colors by exciting atoms at different heights. Conversely, rainbows are created by sunlight backscattering off falling raindrops, and different colors are refracted by slightly different angles. Unfortunately, auroras can’t create waterfalls, but if you plan well and are lucky enough, you can photograph them together. The featured picture is composed of several images taken on the same night last month near the Skógafoss waterfall in Iceland. The planning centered on capturing the central band of our Milky Way galaxy over the picturesque cascade. By luck, a spectacular aurora soon appeared just below the curving arch of the Milky Way. Far in the background, the Pleiades star cluster and the Andromeda galaxy can be found. Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)

Photo by Stefano Pellegrini