INTERPLANETARY SHOCK WAVE SPARKS AURORAS: Surprising forecasters, a minor interplanetary shock wave hit Earth's magnetic field on Jan. 11th. The impact just after 08:30 UT did not trigger a geomagnetic storm. However, strong magnetic fields downstream of the shockfront opened a crack in Earth's magnetosphere. Suddenly, "we were seeing bright blue auroras over Abisko, Sweden," reports Chad Blakley of Lights over Lapland, whose automated webcam captured the display:

https://imgur.com/csMY6Bo

"They were visible in twilight," he says. "My cell phone was buzzing with reports from guides and friends who could see the rare blue Northern Lights dancing overhead."

"Later, the auroras turned green," he says, "and the display is still underway."

The shock wave was not expected. In retrospect, however, perhaps it should have been. On Jan. 8th, a huge filament of magnetism erupted from the surface of the sun. The eruption did not seem to be Earth-directed. However, today's event may have been a glancing blow from the debris.

[link to www.spaceweather.com (secure)]