Last night (Dec. 7th) a minor gust of solar wind gently buffeted Earth's magnetic field. At the Aurora Sky Station in Sweden, above the Arctic Circle, a gentle gust is all it takes to ignite auroras you can reach out and touch ... almost:

Image
© Chad Blakley
"Every night our staff checks spaceweather.com to see what the future may hold," says Sky Station photographer Chad Blakley. "Needless to say, we were all excited when we saw the density of the solar wind rise above 15 protons/cm3. Soon the auroras began, and they did not stop until we all went home six hours later." (For the record, the auroras pictured above were more than 100 km above Blakeley's head.)

A more forceful gust of solar wind is en route to Earth, due to arrive on Dec. 10th. High-latitude sky watchers should remain alert for auroras.

More images: from Marketa Stanczykova of Iceland, Reykjavik; from Borkur Hrolfsson of Þingvellir, Iceland; from Frank Olsen outside Tromsø, Norway; from Fredrik Broms of Kvaløya, Norway; from Börkur Hrólfsson of Reykjavik, Iceland; from Øystein Lunde Ingvaldsen of Bø in Vesterålen, Norway; from Kjetil Skogli outside Tromsø, Norway