BLUE AURORAS: Northern Lights are usually green, and sometimes red. Those are the colors produced by oxygen when it is excited by electrons raining down from space. Micha Bäuml of Straumfjord, Norway, witnessed an appariton of aurora-blue.
High-latitude sky watchers should be alert for auroras on Halloween. A CME is expected to hit Earth's magnetic field on Oct. possibly sparking polar geomagnetic storms. In northern Norway, the show got started early with this display on Oct.