AURORA Taken by Anthony Madden on August 28, 2015 @ Anchorage, Alaska

NORTHERN LIGHTS, NO PARKA REQUIRED: Arctic skies are dimming again after a rare burst of August auroras. For the past few days, Earth has been passing through a region of space where interplanetary magnetic fields opened a crack in the magnetosphere. Solar wind poured in to fuel displays like this one over Anchorage, Alaska:

" The sky was full of lights", says Anthony Madden, who took the picture from Lake Hood Airport on Aug. 28th. "The best part was, it was warm enough that I did not need a parka."

The storms are subsiding now, but they could return on Sept. 2nd when Earth crosses through a fold in the heliospheric current sheet. This is called a "solar sector boundary crossing," and NOAA forecasters estimate a 70% chance of polar geomagnetic storms when it occurs.