Astronomy Picture of the Day

Explanation: Have you ever seen an aurora? Aurorae are occurring again with increasing frequency. With the Sun being unusually dormant over the past four years, the amount of Sun-induced aurorae has been unusually low. More recently, however, our Sun has become increasingly active and exhibiting a greater abundance of sunspots, flares, and coronal mass ejections. Solar activity like this typically expels charged particles into the Solar System, some of which may trigger Earthly aurorae. Two weeks ago, beyond trees and before stars, a solar storm precipitated the above timelapse displays of picturesque aurorae above Ravnastua, Skoganvarre and Lakselv, Norway. Curtains of auroral light, typically green, flow, shimmer and dance as energetic particles fall toward the Earth and excite air molecules high up in the Earth's atmosphere. With solar maximum still in the future, there may be even better opportunities to see spectacular aurorae personally over the next few years.