Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2012 February 9

Trees, Stars, Aurora!
Video Credit & Copyright: Christian Mülhauser; Music: Elemental by Pulse Faction; Path of Stars by Jonathan Geer

Explanation: Have you ever seen an aurora? Auroras are occurring again with increasing frequency. With the Sun being unusually dormant over the past four years, the amount of Sun-induced auroras 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 auroras. Two weeks ago, beyond trees and before stars, a solar storm precipitated the above timelapse displays of picturesque auroras 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 auroras personally over the next few years.

Tomorrow's picture: open space

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