Aurora Outburst

Aurora Outburst

Last night, March 14-15, sky watchers around the Arctic Circle witnessed a magnificent outburst of auroras. "It was utterly amazing," reports Oliver Wright of Abisko, Sweden. "Best I've seen in years of night photography." He took this picture just as the storm was getting started:

"Later, the auroras exploded and just filled the sky!" he said.
Aurora outbursts are often caused by CMEs. In this case however, a CME was not responsible. Instead, the interplanetary magnetic field (IMF) around Earth tipped south. This opened a crack in Earth's magnetic field. Solar wind poured in to fuel the display.