Earlier this week – on October 2, 2013 – a coronal mass ejection struck Earth’s magnetic field. It created a G2-class geomagnetic storm and filled Earth’s northern skies with auroras. Thomas Kast in Finland posted this photo on EarthSky’s Facebook page. He wrote:
Last night (2 October 2013) was a special aurora night and this is only one photo of many. For a long time I wanted to capture auroras with a field of sparse tall trees. The huge layer of faint green in the sky brought out the silhouettes even better than I hoped for. At times it was very foggy as you can see at the bottom. What an amazing atmosphere it was.
Thank you, Thomas!